Compressor assembly

ABSTRACT

An improved, preferably oil-less, air compressor assembly includes a frame and at least a first rotatable cam member mounted to the frame for selective rotation relative thereto. The first cam member has a cam profile. A motor is operatively interconnected with the first cam member for rotating the first cam member. A dual-acting piston assembly includes first and second rods operatively interconnected with a piston received in a piston housing, wherein the piston assembly is mounted relative to the cam profile whereby the piston is stroked upon rotation of the first cam member.

BACKGROUND

This application claims the priority benefit of U.S. provisional application Ser. No. 62/661,898, filed Apr. 24, 2018, the entire disclosure of which is expressly incorporated herein by reference.

This invention relates to an air compressor assembly.

The air compressor and pump markets are flooded with many types of devices, which allows the user the ability to compress fluids to desired pressures. However, many of these devices only offer certain attributes for certain needs. For example, a customer that wants more standard cubic feet per minute (SCFM) will go with a larger compressor/pump unit, but sacrifices mobility and portability of the unit. A customer that chooses a more compact or portable device loses the higher SCFM output. With this, customers have a hard choice when choosing the right size unit for their job. Even in manufacturing, customers have the challenge of integrating large compressors/pumps in small shops that lack space or storage. Therefore, a solution would be to have a compressor/pump that allows for the customer to have the portability, packaging, and SCFM in one unit.

Common solutions to this problem involve the use of compromising both portability and SCFM output by making a compact piston device that runs directly from a motor. However, this causes a drop in overall SCFM since a flywheel and piston design allows for higher torque ratios due to the step in size and inertia of the flywheel. This loss is major for those who need the SCFM, but gain the packaging. This loss can be overcome by adding a portable reservoir or air tank to lessen the load for the compressor/pump. Unfortunately, this adds undesired weight and if the reservoir or tank runs out, the compressor/pump will have to work to fill, causing a downtime or inconsistent flow for the user.

Another common solution is the costly route of using rotary and screw compressor/pumps. This is excellent for high SCFM, but the cost drives towards industrial usage. These units usually take up a lot of space and are hard to maintain. Therefore, the solution needs to also be cost effective, consistent in output, and allow for no compromising.

As noted, known air compressors adopt a wide variety of concepts. For example, vane compressor assemblies have a fixed volume limitation and usually have high pressures. A rotary screw compressor assembly typically requires an enlarged screw with extremely high pressure, and is typically an expensive compressor assembly. A crank slider compressor assembly is a common type of compressor that is inexpensive and uses a piston for pressurization.

These general types of compressor assemblies are generally in three distinct sizes. Stationary units and tanks are large, bulky, and difficult to move, even though they are widely used in businesses. A smaller, medium-size tank has a low-profile that is relatively portable and commonly referred to as a pancake compressor assembly. These compressor assemblies can be limited in their output. Small tank-less assemblies can be used for emergency situations but are limited in size and output thereby limiting the types of end uses.

Known reciprocating air compressors are typically bulky, using a crankshaft design that is orientation specific. The units are typically noisy as a result of the piston head hitting the cylinder and also as a result of incorporating relatively rigid metal components. Such a reciprocating air compressor is typically inefficient since it is a single acting piston, i.e. one stroke per revolution with a complex spring return arrangement. Thus, existing products are oftentimes heavy and immovable, or so small as to be unable to serve the intermediate market. Further, known air compressor arrangements require lubrication, specific line orientation, encounter major vibrations, are noisy, fluctuate in discharge pressure, require cooling, etc.

A need exists for an improved air compressor assembly that provides a simple, compact arrangement that provides a high flow rate with increased consistency, can be used in multiple orientations, and is modular (easy to repair), cost effective, reliable, high operating efficiency, high output, while overcoming at least one or more of the above-described features of the prior art arrangements.

SUMMARY

There is provided an improved air compressor assembly.

A preferred arrangement of the compressor assembly includes a frame and at least a first rotatable cam member mounted to the frame for selective rotation relative thereto. The first cam member has a cam profile. A motor is operatively interconnected with the first cam member for rotating the first cam member. A dual-acting piston assembly includes first and second rods operatively interconnected with a piston received in a piston housing, wherein the piston assembly is mounted relative to the cam profile whereby the piston is stroked upon rotation of the first cam member.

In other preferred embodiments, the compressor assembly may include cam profile or track/grove that captures a follower therein, and a follower arm transmits this movement to operate one or more piston assemblies. The assembly may include multiple drive and driven pulleys of different sizes to vary the drive ratio from the motor to cam assembly.

In still other preferred arrangements, the compressor assembly includes first and second axially spaced apart cam members, where a dual acting piston assembly includes first and second rods extending therefrom, each rod having a cam follower that interacts with one of the separate, spaced apart cam members for coordinated movement of each piston rod (i.e., the cam profiles are synchronized with one another).

The first and second rods extend from opposite ends of the piston housing and are secured to opposite faces of the piston. The cam profile urges opposite movement of the rods relative to the piston housing as the first cam member rotates.

The piston housing is mounted to an axle on which the first cam member rotates.

The assembly further includes first and second followers mounted on each of the first and second rods, the followers each configured to abut the cam profile so that the rods move relative to the piston housing as the first cam member rotates.

The air compressor assembly further includes a second cam member mounted for synchronized, rotational movement with the first cam member.

The air compressor assembly may include a second, dual-acting piston assembly including first and second rods operatively interconnected with a second piston received in a second piston housing. The second piston assembly is mounted relative to the cam profile whereby the second piston is stroked upon rotation of the second cam member.

In one embodiment, the first and second piston assemblies are the same size.

A clutch may be interposed between the first and second cam members wherein the second cam member is selectively operated with the first cam member.

The compressor assembly may include a flywheel rotatably mounted to the frame for selective rotation relative thereto.

The cam profile of the first cam member may include a preselected number of repeated cam profile portions, relative to the size of the first cam member and/or the size of the piston assembly(ies).

A method of making an air compressor assembly includes providing a frame and mounting at least a first rotatable cam member to the frame for selective rotation relative thereto. The method further includes providing the first cam member with a cam profile, operatively interconnecting a motor with the first cam member to rotate the first cam member, and mounting a dual-acting piston assembly, that includes first and second rods interconnected with a piston in a piston housing, relative to the cam profile whereby the piston is stroked upon rotation of the first cam member.

The method further includes providing first and second followers on each of the first and second rods, where the followers are configured to abut the cam profile so that the rods move relative to the piston housing as the first cam member rotates.

A primary advantage is the provision of an oil-less air compressor assembly that is generally portable, has a wide variety of pumped air volume and different pressures.

Another benefit resides in the quiet, efficient, high flow rate (e.g., pumps 6.0 cubic feet per minute (cfm) at 900 revolutions per minute (rpm)), compact, oil-less design in a compact design (e.g., 2′×1.5′×3.5′ footprint) having a simplified assembly with improved output.

Still other benefits and advantages of the present disclosure will become more apparent from reading and understanding the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a compressor assembly driven by a conventional motor.

FIG. 2 is an enlarged perspective view of the compressor portion of the assembly of FIG. 1.

FIG. 3 is an exploded perspective view of the assembly portions of FIG. 2.

FIG. 4 is an elevational view of a first embodiment of the cam member.

FIG. 5 is a side view of the cam member of FIG. 4.

FIG. 6 is a top plan view of the cam member of FIG. 4.

FIG. 7 is a perspective view of a second embodiment of the cam member.

FIG. 8 is a perspective view of a third embodiment of the cam member.

FIG. 9 is an enlarged view of the follower/roller provided at a first end of the piston assembly.

FIG. 10 is a perspective view of a second embodiment of the compressor assembly.

FIG. 11 is an elevational view of the compressor assembly of FIG. 10.

FIG. 12 is a top plan view of the compressor assembly of FIG. 10.

FIG. 13 is an exploded perspective view of the compressor assembly of FIG. 10.

FIG. 14 is an exploded view of one of the multiple piston/cylinder assemblies of the compressor assembly of FIG. 10.

FIG. 15 is a perspective view of a third embodiment of the compressor assembly.

FIG. 16 is a front elevational view of the compressor assembly of FIG. 15.

FIG. 17 is a top plan view of the compressor assembly of FIG. 15.

FIG. 18 is a rear elevational view of the compressor assembly of FIG. 15.

FIG. 19 is a cross-sectional view taken generally along the lines 19-19 of FIG. 16.

FIG. 20 is a cross-sectional view taken generally along the lines 20-20 of FIG. 16.

FIG. 21 is a perspective view of the multi-radial driven pulley and barrel cam subassembly of the compressor assembly of FIG. 15.

FIG. 22 is a front elevational view of the multi-radial driven pulley of the compressor assembly of FIG. 15.

FIG. 23 is in elevational view of the multi-radial driven pulley and barrel cam subassembly of the compressor assembly of FIG. 15.

FIG. 24 is a top plan view of the multi-radial driven pulley and barrel cam subassembly of the compressor assembly of FIG. 15.

FIG. 25 is a perspective view of a connection movement arm used in the compressor assembly of FIG. 15.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of one or more embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. Various exemplary embodiments of the present disclosure are not limited to the specific details of different embodiments and should be construed as including all changes and/or equivalents or substitutes included in the ideas and technological scope of the appended claims. In describing the drawings, where possible similar reference numerals are used for similar elements.

The terms “include” or “may include” used in the present disclosure indicate the presence of disclosed corresponding functions, operations, elements, and the like, and do not limit additional one or more functions, operations, elements, and the like. In addition, it should be understood that the terms “include”, “including”, “have” or “having” used in the present disclosure are to indicate the presence of components, features, numbers, steps, operations, elements, parts, or a combination thereof described in the specification, and do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, parts, or a combination thereof.

The terms “or” or “at least one of A or/and B” used in the present disclosure include any and all combinations of words enumerated with them. For example, “A or B” or “at least one of A or/and B” mean including A, including B, or including both A and B.

Although the terms such as “first” and “second” used in the present disclosure may modify various elements of the different exemplary embodiments, these terms do not limit the corresponding elements. For example, these terms do not limit an order and/or importance of the corresponding elements, nor do these terms preclude additional elements (e.g., second, third, etc.). The terms may be used to distinguish one element from another element. For example, a first mechanical device and a second mechanical device all indicate mechanical devices and may indicate different types of mechanical devices or the same type of mechanical device. For example, a first element may be named a second element without departing from the scope of the various exemplary embodiments of the present disclosure, and similarly, a second element may be named a first element.

It will be understood that, when an element is mentioned as being “connected” or “coupled” to another element, the element may be directly connected or coupled to another element, and there may be an intervening element between the element and another element, e.g. indirectly coupled. To the contrary, it will be understood that, when an element is mentioned as being “directly connected” or “directly coupled” to another element, there is no intervening element between the element and another element.

The terms used in the various exemplary embodiments of the present disclosure are for the purpose of describing specific exemplary embodiments only and are not intended to limit various exemplary embodiments of the present disclosure. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise.

All of the terms used herein including technical or scientific terms have the same meanings as those generally understood by an ordinary skilled person in the related art unless they are defined otherwise. The terms defined in a generally used dictionary should be interpreted as having the same meanings as the contextual meanings of the relevant technology and should not be interpreted as having inconsistent or exaggerated meanings unless they are clearly defined in the various exemplary embodiments.

One skilled in the art will also appreciate that where the terms “generally” or “substantially” are used in the detailed description, the associated claim term is intended to be construed as covering the described component or relationship, as well as variations that have an insubstantial change on the functionality of the component or relationship. For example, the claim term “perpendicular” may refer to first and second components as being “perpendicular” (e.g., oriented 88 to 92 degrees relative to one another), “substantially perpendicular” (e.g., oriented 85 degrees to 95 degrees relative to one another), or “generally perpendicular” (e.g., oriented 80 degrees to 100 degrees relative to one another) as long as the components so arranged would otherwise function without an insubstantial change or fall within the scope and spirit of the present invention.

Turning initially to FIGS. 1-3, there is shown a compressor assembly 100 driven by a motor such as electric motor 102, although other types of motors could be used with equal success. The motor 102 is conventional and forms no particular part of the specific invention herein so that further description of its structure and function is not required for a full and complete understanding of the present disclosure. The motor 102 includes an output or drive shaft 104 that rotates at a predetermined rotational input (e.g., speed, torque, power). The driveshaft 104 of the motor 102 receives a drive member such as drive belt 106. Of course one skilled in the art will appreciate that alternative drive members or transmissions such as direct drive, belt drive, cure drive, etc., could be used as the driving mechanism that operatively interconnects the motor/engine/wheel with a driven member. The drive belt 106 transfers the power output of the motor 102 to the driven member which in this particular instance is a cam assembly or arrangement 120. Preferably, the cam assembly 120 is secured to frame 122 and it will be appreciated that due to the flexibility of the drive belt 106, the motor 102 may or may not be secured to the same frame also. When sold as a part of the compressor assembly system, it may be more convenient to mount the motor to the same frame 122.

More particularly, the drive belt 106 extends around a driven member such as flywheel 124 that is mounted for rotation relative to the frame 122 about a central or rotational axis such as axle 126. In a preferred arrangement, a periphery of the flywheel 124 includes a recess or groove 128 that receives the drive belt 106 therein. In this manner, as the drive shaft 104 rotates at a predetermined rotational input (e.g., speed, torque, power), the flywheel 124 is likewise rotated at a preselected, corresponding rotational speed. The relative diameters of the drive shaft 104 and flywheel 124 determine the drive ratio between the components, although the particular drive ratio may be varied as desired and without serving as a limitation to the present disclosure.

Also mounted for rotation relative to the frame 122, are one or more cam members 140 which are secured for rotation with the flywheel 124 thus driven by the driveshaft. The cam members 140 are joined in any suitable manner for rotation with the flywheel 124, for example, the cam members may be stacked on one and/or both sides of the flywheel. In a preferred arrangement, each cam member 140 a, 140 b, 140 c . . . is substantially identical to one of the other cam members, i.e., each cam member includes a cam profile, which in this particular instance includes a non-circular profile or path 142 (FIG. 4). However, different cam members may have different profiles depending on output requirements for the system. Further, each mounting opening 144 in a cam member 140 receives a mounting member such as an elongated fastener 146 (FIGS. 1 and 2) that extends through aligned openings in adjacent rotational components (e.g., aligned, similar mounting openings in the flywheel 124 and/or adjacent cam member(s)). Here, multiple mounting openings 144/fasteners 146 are provided in the operatively attached flywheel 124 and one or more cam members 140. Specifically, the opening/fasteners are circumferentially spaced about the annular-shaped cam members 140 and/or extend through individual radial spokes 124 b in the flywheel 124. In this manner, the cam assembly 120 (which includes the flywheel 124 and one or more cam members 140) preferably rotates as a single unit relative to the frame 122.

The illustrated cam profile 142 (FIGS. 4-6) is defined at least in part by a non-circular form that transitions from an inner perimeter 150 of the cam member to a larger radius 142 a. Of course one skilled in the art will understand that the cam profile 142 may adopt a wide variety of configurations or conformations depending on the desired movement(s) that is(are) to be imparted in the cam assembly 120. Without limiting the present disclosure, alternative cam profiles are shown in FIG. 7 (a three-lobed cam profile) and FIG. 8 (a five-lobed cam profile), and it is contemplated that still other cam profiles can be used that have a greater or lesser number of lobes, or an open cam design. It is also contemplated that the cam(s) could be the flywheel without departing from the scope and intent of the present disclosure. More particularly, the particular illustrated cam profile 142 is an eccentric path that follows a smooth transition from the inner perimeter of the cam member 140 into the remainder of the cam profile. The smooth transitions along the cam profile provide for quieter operation and associated increased operating life of the cam assembly 120. The same is true for the alternative, multi-lobed cam profiles of FIGS. 7 and 8.

Specifically, the compressor assembly 100 includes first and second dual acting piston assemblies 160. Description of one piston assembly 160 will apply to others unless particularly noted otherwise, and it will also be appreciated that one or more dual acting piston assemblies may be incorporated into the compressor assembly in a variety of manners as described below. Again, although it is envisioned that typically each piston assembly is the same as the other piston assemblies, it is also envisioned that an air compressor assembly may include different sized piston assemblies or different types of piston assemblies (e.g., single acting or dual acting). Piston assembly 160 includes a housing or cylinder 162 that receives a piston 164 therein. The piston assembly 160 is mounted to the frame 122 and positioned for interaction with the cam member 140 that rotates relative to the frame. Extending outwardly through the cylinder 162 from each side of the piston 164 are first and second rods 166. At an outer end of each rod 166 is provided a follower such as roller 168 (FIG. 9). Suitable dimensioning of the cam profile 142 and piston assemblies 160 assures that the rollers 168 provided at opposite ends of the dual acting piston assemblies are in operative engagement with the cam profile. As the cam member 140 rotates, the piston 164 moves or reciprocates in the cylinder 162 and pressurized air is forced or expelled from an associated valve 170 provided at each end of the cylinder. Thus, advancement of the piston 164 toward one of the first and second ends of the cylinder 162 provides pressurized air through the valve 170 provided at that end of the cylinder (while air is introduced into the valve at the other end of the cylinder). Similarly, when the piston 164 is then advanced in the opposite direction toward the other end of the cylinder 162, the air is compressed at the other end so that pressurized air is then provided through the valve 170 at the other end of the cylinder.

In the particular illustration of the cam profile 142 shown in the accompanying drawings, rotation of the cam member 140 through 180° moves the piston 164 from adjacent a first end of the cylinder to adjacent a second end of the cylinder 162. Continued rotation of the cam member 140 through the remaining 180° then moves the piston 164 from adjacent the second end of the cylinder 162 to adjacent the first end of the cylinder. Again, and as noted above, altering the cam profile 142 could alter the number of strokes that an associated piston assembly 160 would undergo during a portion or full rotation of the cam member 140.

In addition, the cam assembly 120 preferably does not contain a metal to metal contact. It is also intended to be an oil-less structure (limited lubrication issues) so that it overcomes problems associated with known compressor assemblies where the compressor assembly must be maintained level/upright to control oil flow. Here, a second cam assembly 120 b and piston assembly 160 b is illustrated on the opposite side of the flywheel 124 and operates in the same manner as the above-described cam assembly and piston assembly. Cooling of the present arrangement can be achieved with air blowing across the assembly such as the pistons assemblies. For example, the “spokes” of the flywheel 124 can be used to advantageously generate air flow as the flywheel is rotated and the air flow passing over the compressor assembly components (e.g., drive motor, bearings, piston assemblies, etc.) will serve to cool the components. Of course, other suitable modifications can be made to enhance cooling air flow (add blades to the flywheel or rotating cam members, or add a centrifugal fan, etc.)

Suitable other modifications include adding additional cam assemblies 120/piston assemblies 160 can be easily made, such as stackable, i.e., added at opposite ends of the compressor assembly 100. One or more of the cam assemblies 120/piston assemblies 160 can be selectively operated via a conventional clutch mechanism (not shown), so that additional compressed air may be selectively added or removed to the system via the clutch mechanism. The orientation of the piston assembly 160 relative to an associated cam member 140 can also be altered to provide ease of assembly, balancing of the load, etc. Although like-sized piston assemblies 160 would be preferred for ease of manufacturing, inventory, replacement, balance, etc., it is also contemplated that different size piston assemblies can be used with equal success, i.e., in a particular compressor assembly, one piston/cylinder arrangement may have an elongated stroke while another would have a short stroke, or piston/cylinder diameters may be different between different piston assemblies.

Using multiple piston assemblies 160 also allows the overall speed of the compressor assembly 100 to be reduced since the multiple piston assemblies provide the desired pressurized air at different points of rotation of the cam member(s) 140. Lower speed of course results in decreased wear and increased life of the compressor assembly 100 and individual components thereof.

In summary, the present invention comprises both common components seen in an average compressor/pump, which is the piston and flywheel. However, this device combines both into a compact package that allows for the desired portability. The device has at least two dual acting, dual rod, piston cylinders that make up the axle of a conjugate cam flywheel. This conjugate cam makes up the spokes of the flywheel, whereas the piston cylinder is stationary.

The device is powered by any suitable drive means to rotate the flywheel and achieve the desired output pressure or flowrate. The piston shaft ends serve as the cam followers that follow the conjugate cam spoke to provide rotational work to linear force to the drive the piston and compress the fluid (air). Valve control allows for the flow direction into and from each cylinder. The dual acting, dual rod, cylinders allow the system to be more compact. The dual rod design also advantageously allows for the rod ends to be the followers. The dual acting cylinders allows for the cylinders to act as if there are four separate cylinders. This also achieves four compression cycles per revolution of the flywheel in a compact, efficient manner. The arrangement also allows for a consistent/higher SCFM.

Different applications will have different requirements for psi, CFM, horsepower, etc. Other known two-stage reciprocating compressors typically have a maximum operating pressure in the range of 175 psi, or high-volume applications operate between 45 to 60 psi, screw compressors at a pressure of 90-125 psi, and a single stage air cooled compressor may range from 30 to 100 psi. A single stage, air-cooled reciprocating motor size is approximately ½ to 10 hp, and a high pressure, two-stage air cooled reciprocating motor size ranging from 1½ to 30 hp. These are ranges of other units in the industry, whereas the present system is suitable for use, for example, up to 200 psi based on the size and specification of the piston cylinders with a ½ hp motor, and a preferred stroke length of 0.5 to 11 inches. These values are exemplary only and need not limit the present disclosure.

FIGS. 10-14 illustrate a second embodiment of a compressor assembly 200. The compressor assembly 200 includes an electric drive motor 202 with an output drive shaft 204. Here, the shaft is a direct drive to the axis of cam assembly 220 which includes first and second axially spaced cam members 220 a, 220 b. As will be appreciated, the cam members 220 a, 220 b are identical and mounted to rotary shaft 222, and are 180° out of phase relative to one another, and that the additional cam member(s) can also act as “flywheels”. The rotary shaft 222 is connected to and driven by output drive shaft 204 of the electric drive motor 202. First and second clamping shaft couplings 224 and a split tapered bushing 226 interconnect the output drive shaft 204 and the rotary shaft 222 so that the rotational drive movement of the electric motor is transferred to the first and second cam members 220 a, 220 b. Each cam member 220 a, 220 b includes a cam profile or path 228 formed on a face thereof, and the cam profiles are disposed in facing, axially spaced relation to one another. Positioned between these profiles are one or more piston/cylinder assemblies 240. Shown here, are four such assemblies 240 circumferentially spaced from one another. Each piston/cylinder assembly 240 includes a piston rod 242 extending axially outward from a respective end of the cylinder, and a ball-shaped member 244 is secured to the terminal end of each piston rod for tracking receipt within a respective cam profile 228. Each piston assembly 240 is secured to a central mounting block 250 with piston mount caps 252 on opposite, axial ends. Flanged mounted ball bearing assemblies 254 are, in turn, secured to respective piston mount caps 252 to rotatably support the shaft 204 and cam members 220 a, 220 b. In operation, drive shaft 204 of the electric motor 202 rotates the cam members 220 a, 220 b. Since the cylinders are held in place, the piston and piston rods 242 axially reciprocate within the respective cylinders, so that pressurized air is expelled from that side of the piston chamber that is decreasing in size and air is drawn into that portion of the piston chamber that is increasing in size. The cam profiles 228 that receive the members 244 mounted on the piston rods 242 translate the rotational movement of the drive shaft 204 into axial reciprocating movement of the piston and piston rods 242 to produce the desired pumping action and resultant pressurized air. As perhaps best evident in FIGS. 11 and 12, the illustrated embodiment of the cam profile 228 provides two complete strokes of each piston cylinder assembly 240 for each revolution of the cam member 220. This ratio, however, may be altered without departing from the scope and intent of the present disclosure.

FIGS. 15-25 show a third embodiment of a compressor assembly 300. The compressor assembly 300 includes a drive motor, such as electric drive motor 302, that rotates drive shaft 304. In a manner similar to the first embodiment, the rotational movement of the shaft 304 is translated to a driven shaft 324 of the cam assembly 312 via a flexible drive member such as drive belt 306. The drive belt 306 extends around a drive pulley 308 that is keyed to the drive shaft 304 and also around one of concentric pulleys 310 of a barrel cam subassembly 312. One skilled in the art will understand that only one size driven pulley 310 could be provided (rather than the multiple sizes as illustrated in these figures) and/or drive pulley 308 may include multiple diameter portions if there is a desire to further vary the drive input and output ratios.

The barrel cam subassembly 312 includes a cam member 320 having a peripheral groove or cam profile 322 that advantageously holds or contacts both sides of an associated follower 352. Shaft 324 (arranged in parallel arrangement with drive shaft 304) is supported by suitable bearings and transfers the rotational movement of the driven pulley 310 to the cam member 320. Air piston/cylinder assemblies 330 are received between mounting plates 332 whereby the cylinders are fixed against axial movement relative to the driven pulley 310. Air from opposite sides of the piston is routed through suitable manifold assemblies that is generally conventional in the art. Thus, the dual acting piston provides pressurized air as the piston axially reciprocates within its associated cylinder housing. One distinction is that cam profile 322 varies along the outer surface of the cam member 320 in an axial direction i.e., parallel to the rotational axis of the driven pulley and rotational axis of the cam member 320.

As particularly illustrated in FIG. 25, one of the connection movement arms 350 is individually illustrated, and it is recognized that each piston cylinder assembly 330 includes its own connection movement arm to transfer the axial movement of rolling member, follower 352 received in the cam profile 322 to a piston/cylinder assembly 330. Suitable mounting openings 356 are provided in the arm 350 for securing the arm to a laterally offset piston rod(s) of an associated air piston/cylinder assembly 330 via mounting arm 354. Thus, in one arrangement, each of the two rods extending from opposite ends of each piston assembly is directly connected via arm 354 to one of the connection movement arms 350 to provide positive direct transfer of the reciprocating movement of the connection movement arm to each piston rod, while in other embodiments only a single rod extends from each piston assembly and is suitably interconnected to the follower via the connection movement arm. Suitable openings 360 are provided in at least one (or both) of the mounting plates 332 to accommodate reciprocating movement of the arm 350 therethrough as the follower 352 axially moves the arm 350 as the arm tracks along the cam profile 322. This arrangement provides for a compact air compressor assembly due to the parallel drive shaft 304 and cam shaft 324, and is even more compact if only a single rod extends from each piston assembly.

This written description uses examples to describe the disclosure, including the best mode, and also to enable any person skilled in the art to make and use the disclosure. Other examples that occur to those skilled in the art are intended to be within the scope of the invention if they have structural elements that do not differ from the same concept, or if they include equivalent structural elements with insubstantial differences. 

We claim:
 1. An air compressor assembly comprising: a frame; at least a first rotatable cam member mounted to the frame for selective rotation relative thereto, the first cam member having a cam profile; a motor operatively interconnected with the first cam member for rotating the first cam member; and a piston assembly including at least one rod operatively interconnected with a piston received in a piston housing, wherein the piston assembly is mounted relative to the cam profile whereby the piston is stroked upon rotation of the first cam member.
 2. The air compressor assembly of claim 1 wherein the piston assembly includes first and second rods extend from opposite ends of the piston housing and are secured to opposite faces of the piston, the cam profile urging opposite movement of the rods relative to the piston housing as the first cam member rotates.
 3. The air compressor assembly of claim 1 wherein the piston housing is mounted to the frame.
 4. The air compressor assembly of claim 1 wherein the piston housing is mounted to an axle on which the first cam member rotates.
 5. The air compressor assembly of claim 1 further comprising first and second followers mounted on each of the first and second rods, the followers each configured to abut the cam profile whereby the rods move relative to the piston housing as the first cam member rotates.
 6. The air compressor assembly of claim 1 further comprising a second cam member mounted for synchronized, rotational movement with the first cam member.
 7. The air compressor assembly of claim 6 further comprising a second, dual-acting piston assembly including first and second rods operatively interconnected with a second piston received in a second piston housing, wherein the second piston assembly is mounted relative to the cam profile whereby the second piston is stroked upon rotation of the second cam member.
 8. The air compressor assembly of claim 7 wherein the first and second piston assemblies are the same size.
 9. The air compressor assembly of claim 7 further comprising a clutch interposed between the first and second cam members wherein the second cam member is selectively operated with the first cam member.
 10. The air compressor assembly of claim 1 further comprising a flywheel rotatably mounted to the frame for selective rotation relative thereto.
 11. The air compressor assembly of claim 10 wherein the flywheel is mounted for rotation with the first cam member.
 12. The compressor assembly of claim 1 wherein the cam profile of the first cam member includes a preselected number of repeated cam profile portions wherein the preselected number of repeated cam profile portions equals one-half of a total number of piston assemblies.
 13. The compressor assembly of claim 1 wherein the cam member includes a groove formed therein that captures a follower, and facing radial surfaces of the groove form first and second cam profiles that engage the follower.
 14. The compressor assembly of claim 1 wherein rotational axes of a drive shaft of the motor and a rotational axis of the rotatable cam member are disposed in offset, parallel relation.
 15. The compressor assembly of claim 1 wherein each piston assembly has only a single rod extending from the piston.
 16. A method of making an air compressor assembly comprising: providing a frame; mounting at least a first rotatable cam member to the frame for selective rotation relative thereto; providing the first cam member with a cam profile; operatively interconnecting a motor with the first cam member to rotate the first cam member; and mounting a piston assembly, that includes at least one rod interconnected with a piston in a piston housing, relative to the cam profile whereby the piston is stroked upon rotation of the first cam member.
 17. The method of claim 16 further including providing first and second rods on the piston, and first and second followers on each of the first and second rods, wherein the followers are configured to abut the cam profile so that the rods move relative to the piston housing as the first cam member rotates. 